Separation of alkali-metal salts



" prises the addition to r. we no RESEARCH (30., OF SAN" SEEARATIUN 0F ALEALLTJIETAL SPJLTEE.

Ito Drawing.

To all whom it may concern: a

it known that l, CLINTQN E; DOLB'EAR, a citizen of'the United States, residing" at city and county of San Francisco and State of California, have invented certain new and useful Improvements in the Separation ct AIkaIi-l 'ietal-Salts, of which the following is a specification. My invention relates to the separation from each other and from their common solution of different alkali-metal salts. My

method briefly stated comprises the addition of free ammonia to the solution.

Described more in detail, my method com-- the solution holding the different salts, of ammonia or such character and in suchv manner that it does not react chemically with these salts, hut forces them to a greater or less extent outof the solution.

I -Dillerent salts the presence of free ammonia in the solution. For example, the chlorides'of alkall metals are very little affected by thepresence of even a large amount ammonia, while the solubility of sulphates of these same alkalimetals are very greatly depressed by comparatively small amounts of ammonia. and

sodium carbonate is rendered almost entirely insoluble in strong; ammonia solutions.

l have also'found that (litlerent alkalimetal salts of the same acid, and the same alkali-metal salts of different acids behave quite differently from each other with the. same concentration of ammonia in their solutions. in other Words, fractional sepa ration of different salts can he eifected lw addition of increasing amounts of ammonia to solutions oi? such salts. To give concrete examples-lf a mixture of sodium ciloride, sodium sulphate and sodium carbonate in aqueous solution is subjected to addition of increasing amounts of ammonia. first sodium sulphate is'quite completely precipitated. As the quantity of ammonia increases sodium carbonate begins to precipitate and finally is almost. completely precipitated. Thus, by separating the precipitated sodium sulphate i'rom the supernatent solution before the. sodium carbonate precipitates, and then add ing more ammonia until the sodium car-- honate precipitated, and separating this are diii erently affected by Application filed. August 13, 1923. Serial 311 0. 658,186.

"from the supernatent solution, separation of sodium sulpl'iate, sodium carbonate and sodium chloride is effected, since the sodium chloride is not precipitated but remains in the solution.

Another example: if to a mixture of potassium and sodium nitrates in aqueous so lution ammonia is added, the potassium nitrate is precipitated very completely, thus effecting" separation of potassium nitrate I from sodiuireuitrate.

""lh examples might he detln'itel g hut lustrate the method and the principle involved.

I claim: i. 'lhat sten in the method of separating carried out infrom each (their different elltali inetal salts held in common in solution, which consists in adding ammonia to the solution to selectivel v precipitate them.

2. The method of separating"- fr'om each other and from their common solution different alkali-metal salts. comprising the addition ct ammonia to the solution to se 'lectiveiy "precipitate them, and successively removing" said precipitated.

Ti lie-t step in the method o1"- separating from each other different alkali-metal salts held in common in solution, which consists in adding ammonia to the solution increasing; amounts to selectively, successively precipitate said salts.

4. The method oi other and from their common forent alkali-metal salts, coinprisu du.

separating from each solution ditv i I a, 5. The method of separating; from each.

other and from theircommonsolutiori difad ferent, alkali-metal salts, comprising these few will. serve to ilg; the ad dition to the solution of ammonia to pr cipitate one of said salts; removing the orecipisalt; adding more ammonia. to the, solution to precipitate a second salt; removing said second precipitated salt; and so tenth.

lin testimony whereof l have signed my name to this specification,

liil'lillitltl ill.

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